TB-500 vs Wolverine Stack (BPC-157 + TB-500)

TB-500

TB-500 is a synthetic seven-residue peptide, Ac-LKKTETQ, matching residues 17 to 23 of the 43-residue actin-binding protein thymosin β4. The stretch it copies lies in the central actin-binding region of thymosin β4; the N-terminal acetyl cap is a synthetic addition, since that position is internal in the native protein. The name is sometimes applied loosely to full-length thymosin β4, and the two should be kept apart: they differ in length, in mass (about 0.9 kDa against about 5 kDa) and in which parts of the parent protein they contain. Most published research concerns the full-length protein, examined in cell culture and in rodent models of skin, cardiac and corneal injury. Work on the fragment alone is far thinner, and it cannot be assumed to share the properties described for the whole protein.

Wolverine Stack (BPC-157 + TB-500)

This blend combines two synthetic peptides, BPC-157 and TB-500, supplied together as one product; it is not a new compound. BPC-157 is a 15-residue peptide whose sequence its originators describe as derived from a protein in gastric juice; almost all of its literature comes from rodent studies, much of it from a single research group, and human data are very limited. TB-500 is the synthetic seven-residue fragment Ac-LKKTETQ of thymosin β4, and most related research concerns the full-length 43-residue protein rather than the fragment. We are not aware of any published study that has tested the two peptides together, so the blend has no literature of its own.

How TB-500 acts

Full-length thymosin β4 binds monomeric G-actin in a one-to-one complex and is a major actin-sequestering protein in many cell types, holding actin in unpolymerised form. Structural studies place the LKKTET motif, shared with the WH2 family of actin-binding domains, at the centre of that contact, flanked by N-terminal and C-terminal segments that also touch actin. A small number of cell studies have reported that the isolated fragment affects endothelial cell migration, but how closely it reproduces the actin binding of the whole protein is not well established. Other activities attributed to thymosin β4 map elsewhere: the N-terminal tetrapeptide Ac-SDKP is released by enzymatic cleavage and has been studied separately.

How Wolverine Stack (BPC-157 + TB-500) acts

The two components are reported to act through different pathways, and no interaction between them has been studied. BPC-157 has no identified receptor; rodent and cell studies have linked it to nitric oxide signalling, to the VEGFR2 pathway in endothelial cells and to focal adhesion kinase and paxillin in cultured tendon fibroblasts. TB-500 reproduces the central actin-binding motif of thymosin β4, which in the full-length protein binds monomeric G-actin and regulates the pool of unpolymerised actin; how far the short fragment shares that binding is not well established.

The records side by side

• Type: TB-500, Heptapeptide (thymosin β4 fragment); Wolverine Stack (BPC-157 + TB-500), Two-peptide blend
• Length: TB-500, 7 amino acids; Wolverine Stack (BPC-157 + TB-500), not recorded
• Molecular weight: TB-500, 889.0 g/mol; Wolverine Stack (BPC-157 + TB-500), not recorded
• Molecular formula: TB-500, C38H68N10O14; Wolverine Stack (BPC-157 + TB-500), not recorded

Reading a comparison

A comparison places two records side by side; it does not merge them. Each description above is drawn from that compound's own record, and the two were not necessarily characterised by the same methods, at the same time, or to the same level of detail. Before comparing any attribute, it is worth establishing that both records describe the substance you think they describe — names are not identifiers, and two entries sharing a name can differ in salt form, stereochemistry or the convention used to state a mass. Where a figure carries no method beside it, the comparison is between two reported numbers rather than between two measurements.